With the popularization of the Internet cable, the sharp increase in information transfer in a variety of forms using the Internet and new services based on the Internet, the volume of network traffic is drastically increasing, and the incremental trend is expected to continue. Accordingly, it is necessary to provide a method of increasing network management efficiency by monitoring traffic for efficient management of a network.
Network performance measurement methods may be generally classified into active measurement (AM) method and passive measurement (PM) methods according to their characteristics. In AM method, an experimental packet is given to a network, and characteristics of delay, loss, etc. shown after the packet passes through the network are mainly measured to analyze performance of the network. In PM methods, a packet that is currently flowing through a network is monitored without exerting influence on network flow, and the amount of traffic, traffic configuration or characteristics, etc. are mainly analyzed on the basis of the collected information.
For Internet protocol (IP) networks, AM uses national Internet measurement infrastructure (NIMI), Surveyor tools, simple network management protocol (SNMP), management information base (MIB), tcpdump working on UNIX, NetFlow of CISCO Systems, and so on.
In current networks, PM is frequently used to measure traffic of the networks. However, PM and AM have their own merits and demerits. Measurement of a network state using PM alone has its limitations, and the AM methods require high cost for system construction, analysis and consulting.
Also, packet transmission of current networks uses single-path-based routing. Although there are a plurality of paths, a current routing technique uses a single path for end-to-end packet transmission, and thus transmitted packets may be concentrated in a specific link and cause congestion. To solve such a problem, current networks depend on a transmission control protocol (TCP) congestion control mechanism. However, the TCP congestion control mechanism does not operate until congestion occurs in a specific packet transmission path, merely adjusts the amount of packet transmission of a host, and cannot use a plurality of paths.
In addition, since monitoring protocols such as SNMP and NetConf for monitoring network performance of the current Internet use the same transmission packet as data packets, monitoring information for monitoring a transmission state of data packets cannot be transmitted when a data packet transmission failure occurs. This means that, when a problem occurs in a network, it is difficult to accurately diagnose the problem and find a cause of the problem. Such a problem occurs because current network monitoring information uses the same protocol, such as TCP and user datagram protocol (UDP), on the data layer, and a router or a switch handles all monitoring information in the same manner as data. It is necessary to provide a traffic monitoring method and a transmission path control method for solving these problems.